1. Field of the Invention
The present invention generally relates to an indication display unit for a vehicle wherein indicated various information concerning driving operation such as revolution frequency of engine, residual fuel quantity and so on are visually observed by the images reflected on a reflecting member, and more particularly, to an indication display unit suitably for so-called a head-up display wherein the indicated images are projected to the reflecting member to be visually observed by a driver, while being overlapped with an outside scenery viewed through the windshield thereof.
2. Description of the Prior Art
Referring to FIG. 6, there is illustrated an example of a conventional indication display unit for a vehicle which employs the above-mentioned head-up display.
In FIG. 6, the numeral 11 represents a projector, secured to a ceiling 10 in the car room, for indicating various vehicle information such as a car speed or the like. A semi-translucent mirror generally designated at 12 is provided on a dashboard 30 disposed in front of a windshield 20. An image 13 indicated on the projector 11 is projected to the semi-translucent mirror 12 to be reflected thereon so as to overlappedly observed with an outside scenery viewed through the windshield 20 from the direction of the driver seat.
By virtue of this arrangement, the driver is allowed to visually recognize the vehicle operational information such as the engine speed, residual fuel quantity and so on without averting his visual field to a greater extent during the traveling.
Since the projector 11 is attached to a car room ceiling 10, it is possible to provide more space for accommodating other instruments in the dashboard 30. With this arrangement, a distance from the projector 11 to the semi-translucent mirror 12 becomes larger, and the projected image can be observed at a farther position with a high visual recognizability.
In the case that, as described above, the projector is mounted on the car room ceiling, however, the projector is normally provided just above the driver seat due to optical constraints, and as a result, the prior art indication display unit with the above arrangement presents such problems that the clearance between the driver's head and the lower portion of the projector is caused to decrease, thereby some cooped-up feeling is given to the driver.